Unacceptable service from this Renew-IT branch!!!

My vehicle was booked in at Renew-IT Rivonia on the 20th August for a scratch to be repaired on the passenger rear door. I was notified by my Tracking company on the 26th August that they were not picking up a signal for my tracking unit as the battery had been disconnected. I tried contacting Renew-IT Rivonia for 2 days to speak to the Service delivery manager (Nomsa), whom was never available each time I called. After chatting to the branch manager Bianca, I was notified that my battery had run flat/dead. They could not explain why or how the battery had run flat and it was totally unacceptable to me that a new car's battery runs dead in less than 5 days. My battery was never faulty and this is a new car. We all hear these horror stories about panel beaters and when I first walked into Renew-IT, i thought I'm dealing with the best in the industry. It is very unsettling entrusting a new vehicle to a panel beater who can't explain why your car battery died? Was someone fiddling with the battery? Did they remove the battery? This is unacceptable and I shall not allow any panel beater to take advantage of clients.